1. Field of the Invention
The present invention relates to a pulse detecting apparatus which detects arterial pulses by means of a pressure sensor.
2. Related Art
In oriental medicine, the conditions of a patient are determined by sphygmic diagnosis solely relying on the sense of touch of the arterial pulses on the "sunko", that is, the processus styloideus radii in the inner side of the wrist. In the sphygmic diagnosis of the oriental medicine, the pulses on the "sunko" are classified into those on three spots, such as upper, middle and lower spots which are referred to as "shun", "khan" and "shaku" and two kinds of pulsation condition "myakki" on the pulse route "keimyaku" appeared on respective spots are sensed.
The term "shun" means the distal end side of the artery of the wrist. The pulses on the "shun" represent the health conditions of a patient from the head to the chest. The term "khan" means the middle artery of the wrist between the distal end and the heart. The pulses on the "khan" represent the health conditions between the chest and the navel. The term "shaku" means the heart side of the artery in the wrist and the pulses on the "shaku" represents the health conditions between the navel and the toe.
A sphygmic diagnosis apparatus in which arterial pulses are detected from the artery of a human being by means of sensors such as an infrared ray sensor or a pressure sensor for performing the diagnosis by observation of the sphygmogram has heretofore been known as is disclosed in the specification of the Japanese Examined Patent Publication No. Sho 57-52054.
The disclosed diagnosis apparatus comprises three pressure sensors 61, 62 and 63, each including, for example, a piezoelectric microphone, for converting the arterial pulses on the three spots such as "shun", "khan", and "shaku" of the "sunko" into electrical signal waves and a cuff band 65 which is mounted on the wrist 64 of a patient for biasing the pressure sensors 61, 62 and 63 upon the artery of the wrist as shown in FIG. 5.
The pressure sensors 61, 62 and 63 are disposed on the wrist 64, that is, on and along the artery above the radius and the cuff 65 is wrapped around the wrist. Compressed air is pumped into an air bag (not shown) provided on the cuff 65 from a pneumatic pump via a conduit 66. Changes in arterial pulses can be measured by adjusting the amount of the pumped air to change the pressure applied upon the artery (hereafter referred to as "measured pressure").
The pressure sensors 61, 62 and 63 are connected with an electromagnetic oscillograph and the like through connection codes 61a, 62a and 63a, respectively so that the measured arterial pulses are recorded on a recording paper for observing the sphygmogram.
A pressure at which the blood begins to flow (hereinafter referred to as "high measured pressure" after the blood flow has been blocked by strongly biasing the pressure sensors upon the artery above the radius by pumping a lot of air into the air bag and the biasing pressure is gradually decreased is referred to as "chin" in the oriental medicine and a pressure immediately before the pulses do not occur hereinafter referred to as low measured pressure) when the biasing pressure is further decreased is referred to as "fu" in the oriental medicine. The pulses at these "chin" and "fu" are required for sphygmic diagnosis. However, although the prior art pulse detecting apparatus is capable of detecting the pulses for all biasing pressures when the biasing pressure upon the artery is changed, it does not have means for determining the pulses necessary for sphygmic diagnosis, that is, the pulses at "chin" and "fu". The pulses at "chin" and "fu" are determined based on experience. Therefore, there is a problem that experiences are required for diagnose the illness by the sphygmic diagnosis.
The present invention was made under such circumstances. It is an object of the present invention to provide a pulse detecting apparatus which is capable of obtaining the accurate measured pressures, from which pulses necessary for the pulse diagnosis can be obtained, that is the values of "chin" and "fu".